Piston for dashpots



L JAENICHEN PISTON FOR DAS/HPOTS Filed Aug. 5,

March M Patented Mar. lll, 1924i.,

narran stares trattasi recteur caerse.

LOUIS d'A-IENTCHEN, OF lDlETROT, MICHIGAN, SSIGNOR TO THE STANDD COMPUT-ING SCALE COMPANY, 01E` DETROIT, MICHIGAN, A. CORPORATION OF MICHIGAN.

PISTON FOR DASHPOTS.

Application filed August 5, 1922. Serial No. 579,855.

To all whom it may concern.'

Be it known that T, Louis JAENICHEN, a citizen of the United States, andresiding at Detroit, in the county of Wayne and State of Michigan, haveinvented a new and Tmproved Piston for Dashpots, of which the followingis a specification. This invention relates to the construction of thepistons of dash-pots which are employed to reduce the rate of movementof the parts of computing scales and other vibrating mechanisms, and itsobject is to provide a piston of this character which k willautomatically accommodate itself to the variations in viscosity of theliquids used in dash-pots due to temperature changes.

This invention consists in a dash-pot piston having a passage forliquids, a valve to vary the eective area of this passage, and automaticmeans to move the valve with the changes in temperature.

Tt further consists in manually operable means to change the effectivearea of said passage.

lit also consists in the details of construction illustrated in theaccompanying drawings and particularly pointed out in the claims.

1n the drawings, Fig. 1 is a central longitudinal section of a dash-potand a piston therein embodying the present invention. Fig. 2 is an endelevation thereof. Figs. 3 and 4 are end elevations of the piston withthe valve thereof in two positions. Fig. 5 is a section on the line 5 5of Fig. 1.

Similar reference characters refer to like parts throughout the severalviews.

Oils of various kindsv are the usual liquids employed indash-potsbecause such liquids evaporate very slowly. These liquids, however, areobjectionable because their viscosities are greatly affected by changesin temperature so that the rate of movement of the same piston in thedash-pot under the same pressure is much higher during warm weather. Themovements of the pistons through the liquids vin the dash-pots areregulated by the passages infthe pistons through which the liquids flowas the pistons move back and forth in the dash-pots, and means are herepresented for automatically opening and closing such passages as theoils in the dash-pots become thinner or thicker with rising or fallingtemperatures. While dash-pots may have any desired cross section and maybe in any desired position, they are usually cylindrical and verticaland the present construction will be described accordingly.

The dash-pot shown in the drawing has a body 1 and a head 2 providedwith a funnel 8 of any desired character to conduct splashed-up liquidback into the body 1. The cup-shaped piston 5 has a hub 6 to which thepiston rod is attached, preferably by screwing the rod into the hub andse curing it in position by a jamb nut 7.

Slidable within the tube 4; is a valve stem 8 provided with a transversepin 9 slidable in the slots 10 in the tube 4 so that this stem may slidein the tube without turning. The stem has an eye 12 at its outer end sothat it may be connected to the mechanism whose movements are to beaffected by the dashpot. The stem is threaded at 13 to receive the nut14 whose skirting 15 is internally threaded to receive the bushing 16.The piston rod d has a collar 17 at its outer end which is between thebushing and nut, and the relative positions of the eye 12 and the piston5 may therefore be carried by turning the nut 1d.

Rotatable on the inner end of the stem 8 is a disk valve 19 havingnotches 2O which are adapted to aline with the openings 22 in the head23 of the piston 5. This valve may be held in Vposition by a collar 24and a washer 25. The valve has a flange 26 which is slotted to receivethe outer end of the two-metal. spiral thermostat 27 whose inner end issecured in a slot 28 across the inner end of the stem 8. This inner endof the thermostat is preferably so rigidly'attached to the stem that itsupports the washer 25 and the valve. The operation of this device is asfollows.

The adjuster preferably works in a room of moderate temperature andadjusts the valve 19 relative to the pins 9 in the stem 8 by means ofthe thermostat 27 and after placing the cylinder head 2 on the pistonrod 4 adjusts the slots 10 in the piston rod relative to the holes v22in the piston. The stem 8 is then inserted and adjusted within the tube4 by means of the nut 14: and

the piston inserted in the cylinder 1 which has previously been filledwith proper liquid.

The head 2 having been attached and the between the valve and the pistonhead 23 until the desired retardation is secured. Space is left betweenthe valve and the head 23 so that the liquid may flow between them fromthe notches 2O to the openings 23 when the valve is at the limit of itsclosing movement, as shown in F ig. 3, which is when the highestexpected temperature is reached. When the temperature is at the lowestpoint for which this dash pot is designed, the notches 2O and holes 22are in alinement, as shown in Fig. 4.

'Ihe details of construction, the number of the passages, and theproportions of the parts may all be changed by those skilled in the artwithout departing from the spirit of my invention as set forth in thefollowing claims.

I claim 1. In a dash-pot, a cylinder, a piston therein having an openingtol permit the passage of liquids, a valve to control the e'ective areaof said opening, manually operable means to vary the position of thevalve relative to said opening, and automatic means to vary the positionof the valve relative to said opening independent of said manuallyoperable means. l 2. In a dash-pot, -a cylinder, a piston therein havingan opening to permit the passage of liquids, .a valve to control theeffective area of said opening, manually operable means to vary theposition of the valve relative to said opening, and a thermostat toposition the valve relative to said opening independent of said manuallyoperable means.

3. In a dash-pot, a cylinder,` a piston therein having openings topermit the passage of tliquids, a notched valve to control the eectiveareas of said openings, manually operable means to vary the distancefrom the valve to the openings in the piston, and a thermostat to rotatethe valve.

4. In a dashpot, a cylinder, a piston therein having openings to ermitthe passage of liquids, a valve aving notches adapted to register withthe openings in the y Maasai piston, and a thermostat adapted to rotatethe valve to control the eective areas of the passages for the liquids.

5. In a dash-pot, the combination 'of a piston slidable therein andhaving openings, a piston rod attached to the piston, a stem slidablymounted in the piston rod, a valve rotatably mounted on the inner end ofthe stem adjacent the openings in the piston and having notches adaptedto register with the openings in the piston, means to vary the distancebetween the valve and piston, and,` means to rotate the valve relativeto the piston.

6. In a dash-pot, the combination of a cylinder, a cup-shaped pistonslidable therein and having openings in its head, a piston rod attachedto the piston, a stem slidably mounted in the piston rod, Ya valverotatable on the inner end of the stem adjacent the piston head andhaving notches adapted to register with the openings in the piston head,automatic means to rotate the valve relative to the piston, and means atthe outer end of the piston rod engaging the outer end of the stem toslide it longitudinally of the rod to control the distance `between the*valve and piston head.

,openings in its head, a `piston rod attached to the piston, a stemslidably mounted in the piston rod,la valve rotatably mounted on theinner end of the stem adjacent the piston head and having notchesadapted to register with vthe openings in the piston head, means to varythe distance between the valve and piston head, and means to rotate thevalve relative to the pistonihead comprising 'a spiralthermostatattached to the end of the stemand to said valve.l

8. In a dash-pot, a cylinder, va piston therein, and automatic means andmanually operable means adapted to act independent of each other tovary'the speed of liquids passing from one end of the cylinder to theother. LOUIS JAENICI-IEN

